[Bug 1803718] [NEW] RPC helper segfault - Ubuntu 18.04LTS

Aidan Walton aidan.walton at gmail.com
Fri Nov 16 14:18:12 UTC 2018


Public bug reported:

I created a very simple RPC helper configuration as described in 
http://conntrack-tools.netfilter.org/manual.html

After starting conntrackd, the ct_helper.so causes a segmentation fault as soon as a packet hits the -j CT target in iptables.
conntrackd crashes ungracefully with lock files preventing restart.

conntrackd config:
# Default debian config. Please, take a look at conntrackd.conf(5)

General {
	HashSize 8192
	HashLimit 65535

        Syslog on

        LockFile /var/lock/conntrackd.lock

	UNIX {
		Path /var/run/conntrackd.sock
		Backlog 20
	}

	SocketBufferSize 262142
	SocketBufferSizeMaxGrown 655355

	# default debian service unit file is of Type=notify
	Systemd on
}

Stats {
	LogFile on
}

Helper {
	Type rpc inet udp {
                QueueNum 1
		QueueLen 10240
                Policy rpc {
                        ExpectMax 1
                        ExpectTimeout 300
                }
        }
        Type rpc inet tcp {
                QueueNum 2
		QueueLen 10240
                Policy rpc {
                        ExpectMax 1
                        ExpectTimeout 300
                }
        }
}

nfct list helper
{
	.name = rpc,
	.queuenum = 2,
	.l3protonum = 2,
	.l4protonum = 6,
	.priv_data_len = 0,
	.status = enabled,
};
{
	.name = rpc,
	.queuenum = 1,
	.l3protonum = 2,
	.l4protonum = 17,
	.priv_data_len = 0,
	.status = enabled,
};


iptables rule:
-A OUTPUT -d 10.0.0.0/24 -p udp -m udp --dport 111 -m comment --comment "Load RPC user space helper for outgoing calls to RPC on other local machines (See /etc/conntrackd/conntrackd.conf)" -j CT --helper rpc
-A OUTPUT -d 10.0.0.0/24 -p tcp -m tcp --dport 111 -m comment --comment "Load RPC user space helper for outgoing calls to RPC on other local machines (See /etc/conntrackd/conntrackd.conf)" -j CT --helper rpc

syslog:

Nov 16 15:06:54 mx systemd[1]: Started Conntrack Daemon.
Nov 16 15:06:54 mx conntrack-tools[17623]: netlink event socket buffer size has been set to 262142 bytes
Nov 16 15:06:54 mx conntrack-tools[17623]: configuring helper `rpc' with queuenum=2 and queuelen=10240
Nov 16 15:06:54 mx conntrack-tools[17623]: policy name=rpc expect_timeout=300 expect_max=1
Nov 16 15:06:54 mx conntrack-tools[17623]: helper `rpc' configured successfully
Nov 16 15:06:54 mx conntrack-tools[17623]: configuring helper `rpc' with queuenum=1 and queuelen=10240
Nov 16 15:06:54 mx conntrack-tools[17623]: policy name=rpc expect_timeout=300 expect_max=1
Nov 16 15:06:54 mx conntrack-tools[17623]: helper `rpc' configured successfully
Nov 16 15:06:54 mx conntrack-tools[17623]: initialization completed
Nov 16 15:06:54 mx conntrack-tools[17623]: -- starting in console mode --
Nov 16 15:07:12 mx kernel: [73016.216826] conntrackd[17623]: segfault at 4 ip 00007f7a25091eab sp 00007ffee3341cb0 error 6 in ct_helper_rpc.so[7f7a25091000+2000]

** Affects: conntrack-tools (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1803718

Title:
  RPC helper segfault  - Ubuntu 18.04LTS

Status in conntrack-tools package in Ubuntu:
  New

Bug description:
  I created a very simple RPC helper configuration as described in 
  http://conntrack-tools.netfilter.org/manual.html

  After starting conntrackd, the ct_helper.so causes a segmentation fault as soon as a packet hits the -j CT target in iptables.
  conntrackd crashes ungracefully with lock files preventing restart.

  conntrackd config:
  # Default debian config. Please, take a look at conntrackd.conf(5)

  General {
  	HashSize 8192
  	HashLimit 65535

          Syslog on

          LockFile /var/lock/conntrackd.lock

  	UNIX {
  		Path /var/run/conntrackd.sock
  		Backlog 20
  	}

  	SocketBufferSize 262142
  	SocketBufferSizeMaxGrown 655355

  	# default debian service unit file is of Type=notify
  	Systemd on
  }

  Stats {
  	LogFile on
  }

  Helper {
  	Type rpc inet udp {
                  QueueNum 1
  		QueueLen 10240
                  Policy rpc {
                          ExpectMax 1
                          ExpectTimeout 300
                  }
          }
          Type rpc inet tcp {
                  QueueNum 2
  		QueueLen 10240
                  Policy rpc {
                          ExpectMax 1
                          ExpectTimeout 300
                  }
          }
  }

  nfct list helper
  {
  	.name = rpc,
  	.queuenum = 2,
  	.l3protonum = 2,
  	.l4protonum = 6,
  	.priv_data_len = 0,
  	.status = enabled,
  };
  {
  	.name = rpc,
  	.queuenum = 1,
  	.l3protonum = 2,
  	.l4protonum = 17,
  	.priv_data_len = 0,
  	.status = enabled,
  };

  
  iptables rule:
  -A OUTPUT -d 10.0.0.0/24 -p udp -m udp --dport 111 -m comment --comment "Load RPC user space helper for outgoing calls to RPC on other local machines (See /etc/conntrackd/conntrackd.conf)" -j CT --helper rpc
  -A OUTPUT -d 10.0.0.0/24 -p tcp -m tcp --dport 111 -m comment --comment "Load RPC user space helper for outgoing calls to RPC on other local machines (See /etc/conntrackd/conntrackd.conf)" -j CT --helper rpc

  syslog:

  Nov 16 15:06:54 mx systemd[1]: Started Conntrack Daemon.
  Nov 16 15:06:54 mx conntrack-tools[17623]: netlink event socket buffer size has been set to 262142 bytes
  Nov 16 15:06:54 mx conntrack-tools[17623]: configuring helper `rpc' with queuenum=2 and queuelen=10240
  Nov 16 15:06:54 mx conntrack-tools[17623]: policy name=rpc expect_timeout=300 expect_max=1
  Nov 16 15:06:54 mx conntrack-tools[17623]: helper `rpc' configured successfully
  Nov 16 15:06:54 mx conntrack-tools[17623]: configuring helper `rpc' with queuenum=1 and queuelen=10240
  Nov 16 15:06:54 mx conntrack-tools[17623]: policy name=rpc expect_timeout=300 expect_max=1
  Nov 16 15:06:54 mx conntrack-tools[17623]: helper `rpc' configured successfully
  Nov 16 15:06:54 mx conntrack-tools[17623]: initialization completed
  Nov 16 15:06:54 mx conntrack-tools[17623]: -- starting in console mode --
  Nov 16 15:07:12 mx kernel: [73016.216826] conntrackd[17623]: segfault at 4 ip 00007f7a25091eab sp 00007ffee3341cb0 error 6 in ct_helper_rpc.so[7f7a25091000+2000]

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